The Government is being urged to challenge the United States over plans to extend a crackdown on American tax dodgers to New Zealand.
US law compels financial institutions to provide information about US citizens to its tax agencies.
Tax experts say domestic superannuation funds could incur extra costs in complying with the rules.
The Trustees Corporations Assocation says American tax cheats are unlikely to use Kiwisaver funds and the Government should challenge the US.
Revenue Minister Peter Dunne says the Government is still considering the issue.